1. Field of the Invention
This invention relates to a disk cartridge which rotatably contains a flexible disk or a hard disk, or particularly an optical disk in a case.
2. Description of the Related Art
A flexible disk, an optical disk or an optomagnetic disk as an information recording carrier is generally used by setting it in a recorder/reproducer such as a disk player or the like in the form of a disk cartridge contained in a case.
A conventional disk of this type is known which is contained in a case with a slide shutter for opening a pickup insertion hole and a driving shaft insertion hole formed in the case when the disk is being used and closing them when the disk is not being used. The slide shutter is provided to prevent dust from adhering to the disk, damage to the disk, and any large change in temperature affecting the disk.
However, when a large quantity of data is momentarily recorded or reproduced in an optical disk or the like, a plurality of pickup insertion holes are required. If the plurality of pickup insertion holes are formed in the disk's cartridge, shutters are needed for simultaneously opening all the pickup insertion holes and the driving shaft insertion hole when the disk is being used, or closing the same when the disk is not being used, so as to protect the disk against dust and the like, but a problem may arise in that, if a unidirectional slide shutter is employed to open and close these holes, the entire disk cartridge must be increased in size.
Use of a rotary shutter has been considered, but if the rotary shutter is opened and closed by a slider, coupling a section of the shutter it to the slider must be disposed outside a disk rotating region. The distance the slider has to slide is increased, and there are further problems in that a shutter opening and closing mechanism increases in size, the distance a spring has to travel to close the shutter is increased, and the difference between the shutter operating force when the shutter is opened and when it is closed becomes large. If a slider having a linear motion is engaged with a rotary shutter having a rotating motion, there is a position where the shutter opening and closing forces become very strong. Thus, in some cases, the shutter is not opened or closed, and the shutter is deformed by this very strong force. Further, there are methods of reducing the sliding distance of the slider so that a reduction gear is employed or disposing the position of interlocking the slider to the shutter at the end of a sliding range of the slider with respect to the slider sliding direction. However, in the former method, a space in which the shutter opening and closing mechanism is placed is increased or a larger shutter opening or closing force is required. In the latter method, the direction in which the slider force acts is different from the shutter force operating direction so that the slider and the shutter are hardly operated or the shutter is deformed by forcibly operating. Thus, the construction of this mechanism is complicated.
The inventors have proposed a disk cartridge provided with a rotary shutter in combination with a turning shutter. In such a disk cartridge, the outer diameter of the rotary shutter and the arm length of the turning shutter are so large that some problems arise so that deflection of the shutters occurs in a portion thereof near the driving shaft insertion hole and a gap between the shutters and the case is liable to permit dust to enter into the disk cartridge. It is also harder to rotate the rotary shutter in case of supporting it at the outer periphery thereof than in the case of supporting it at the inner periphery thereof. Therefore, it is preferable to support the rotary shutter at the inner periphery thereof. However, it is necessary to consider that the inner periphery of the rotary shutter overlaps the moving area of the turning shutter. Unless the shutters are supported sufficiently, the rotary shutter will skew with respect to its axis of rotation, or the outer periphery of the rotary shutter will rub against the case to cause a braking action thereto, so that there will be problems in that the operating force of the rotary shutter or the shutters will not be able to open and close smoothly.
In case supporting portions which movably support the rotary shutter and the turning shutter or position these shutters are made of synthetic resin, such portions are cut easily by the shutters. The worn powder from these portions adheres to the disk surface so that an error in reading occurs or the damage to the disk surface is done. In case a surface supporting the disk is made of synthetic resin, dust easily adheres to the disk surface due to static electricity and an error in reading occurs.